1. Field of the Invention
This invention relates to a semiconductor laser beam source apparatus provided with a semiconductor laser. This invention particularly relates to a semiconductor laser beam source apparatus provided with a semiconductor laser and a means for preventing moisture condensation from arising on an optical path of a laser beam emitted by a semiconductor laser.
2. Description of the Prior Art
Light beam scanning apparatuses wherein a light beam is deflected and scanned by a light deflector have heretofore been widely used, for example, in scanning recording apparatuses and scanning read-out apparatuses. As one of the means for generating a light beam in the light beam scanning apparatuses, a semiconductor laser is used. The semiconductor laser has various advantages over a gas laser or the like in that the semiconductor laser is small, cheap and consumes little power, and that the laser beam can be modulated directly by changing the drive current.
From the viewpoint of service life, efficiency, laser beam emission intensity, and the like, the semiconductor laser should preferably be operated at as low temperatures as possible. Therefore, for example, a cooling element is mounted on a mount for supporting the semiconductor laser, and the semiconductor laser is cooled during operation. However, when the semiconductor laser is cooled and the temperature of the semiconductor laser becomes lower than the ambient temperature, moisture condenses on the surface of the semiconductor laser. Moisture condensation adversely affects the operation of the semiconductor laser by, for example deteriorating the electric insulation. Further, when moisture condenses on a laser beam outlet face, the formed droplets act as a lens and adversely affect the convergence and directivity of the laser beam.